Background: The application of enantioselective capillary electrophoresis approach for
the assessment of the enantiomeric purity of chiral molecules is receiving increased attention. Abscisic
acid is one of the chiral sesquiterpenic plant growth regulators that regulate various ecological
and physiological roles in higher plants. Enantiomeric determination of ABA is of great concern because
of the different biological activity of its enantiomers.
Materials and Methods: In this study, we investigated the enantioseparation selectivity of ABA by
incorporating native β-cyclodextrins (β-CD) and its derivatives as chiral modifiers in the background
electrolyte of an enantioselective capillary zone electrophoresis system. Electrophoretic aspects
that affect the enantiomeric separation, such as pH, types of β-CD and its concentration, applied
voltage, injection pressure and time, were studied and optimised.
Results and Discussions: An enhancement in enantioseparation was achieved in a bare fused-silica
capillary (64.5 cm × 50 mm i.d.) using a background electrolyte solution consisting of (2-hydroxypropyl)-
β-CD (80 mM) solubilised in 100 mM phosphate buffer adjusted to pH 5.9 with NaOH,
operated under normal polarity mode (25 kV) at 25°C, and using hydrodynamic injection (75 mbar
for 10s). Relative standard deviations of (intra- and inter-day) ≤ 3.23% and ≤ 1.39% for migration
times and enantiomeric fractions (EF) were achieved using the proposed method.
Conclusion: The proposed chiral capillary electrophoretic method offers advantages in terms of
enantioselectivity and analysis times, which can serve as a reliable platform for the stereoisomeric
analysis of ABA.